Fig. 4

Schematic illustration of the protein leverage effect. The solid blue circle shows the bi-coordinate regulatory target for protein, non-protein energy (carbohydrate and fat) and total energy (the blue negative diagonal) in a hypothetical reference diet (Diet 1). When protein is diluted with carbohydrate and fat (solid red arrow), the strong protein appetite ensures that absolute protein intake remains constant (vertical black line). Consequently, fat and carbohydrate intake increases (dashed red arrow) as does total energy intake (dotted red arrow) as a passive consequence of strong protein regulation